Polyethylene films with matte surface

Abstract

Embodiments of monolayer and multilayer films which provide an improved matte surface are disclosed. The monolayer film or an outer layer of the multilayer films comprise greater than 50% by weight of a first polyethylene having a density of at least 0.935 g/cm3 and a melt index (I2) of 0.9 g/10 minutes or less, and less than 50% by weight of a second polyethylene having a density less 0.935 g/cm3 and a melt index (I2) of 20 g/10 minutes or less, wherein the film exhibits an external gloss of less than 20 units when measured at 45 according to ASTM D2457 and a haze greater than 60% when measured according to ASTM D1003.

The invention claimed is: 
     
       1. A film comprising:
 greater than 50% by weight of a first polyethylene having a density of at least 0.935 g/cm 3 , a melt index (I 2 ) of 0.9 g/10 minutes or less, a melt index (I 10 ) of 1.2 g/10 minutes to 12 g/10 minutes, and a melt flow ratio (I 10 /I 2 ) of 7 to 50; and 
 less than 50% by weight of a second polyethylene having a density less 0.935 g/cm 3 , a melt index (I 2 ) of 20 g/10 minutes or less, a melt index (I 10 ) of 5 g/10 minutes to 150 g/10 minutes, and a melt flow ratio (I 10 /I 2 ) of 7 to 15; wherein 
 the film is a monolayer film exhibiting an external gloss of less than 20 units when measured at 45° according to ASTM D2457 and an external haze greater than 60% when measured according to ASTM D1003; 
 the melt index (I 2 ) is measured according to ASTM D1238 at 190° C. and 2.16 kg load; and 
 the melt index (I 10 ) is measured according to ASTM D1238 at 190° C. and 10 kg load. 
 
     
     
       2. The film of  claim 1 , wherein the film exhibits an external gloss of less than 12 units, a haze greater than 70%, or both. 
     
     
       3. The film according to  claim 1 , further comprising less than 50% by weight of an opacifier. 
     
     
       4. The film according to  claim 1 , wherein the film comprises less than 50% by weight of a low density polyethylene. 
     
     
       5. The film according to  claim 1 , wherein the first polyethylene is a medium density polyethylene. 
     
     
       6. The film according to  claim 1 , wherein the second polyethylene is a linear low density polyethylene. 
     
     
       7. The film according to  claim 1 , wherein the film is substantially free of polypropylene. 
     
     
       8. The film according to  claim 1 , wherein the film is comprised of at least 80% by weight polyethylene. 
     
     
       9. An article comprising the film of  claim 1 , wherein the article is a flexible package, and wherein the film has a thickness of about 15 to about 300 microns. 
     
     
       10. A film comprising:
 (a) a first outer layer comprising (i) greater than 50% by weight of the first outer layer of a first polyethylene having a density of at least 0.935 g/cm 3 , a melt index (I 2 ) of 0.9 g/10 minutes or less, a melt index (I 10 ) of 1.2 g/10 minutes to 12 g/10 minutes, and a melt flow ratio (I 10 /I 2 ) of 7 to 50, and (ii) less than 50% by weight of the first outer layer of a second polyethylene having a density less 0.935 g/cm 3 , a melt index (I 2 ) of 20 g/10 minutes or less, a melt index (I 10 ) of 5 g/10 minutes to 150 g/10 minutes, and a melt flow ratio (I 10 /I 2 ) of 7 to 15; and 
 (b) at least one base layer comprising a polyolefin; wherein 
 the film is a monolayer film exhibiting an external gloss of less than 20 units when measured at 45° according to ASTM D2457 and an external haze greater than 60% when measured according to ASTM D1003; 
 the melt index (I 2 ) is measured according to ASTM D1238 at 190° C. and 2.16 kg load; and 
 the melt index (I 10 ) is measured according to ASTM D1238 at 190° C. and 10 kg load. 
 
     
     
       11. The film of  claim 10 , wherein the film exhibits an external gloss of less than 12 units, a haze greater than 70%, or both. 
     
     
       12. The film of  claim 10 , wherein the first outer layer further comprises less than 50% by weight of an opacifier based on the weight of the first outer layer. 
     
     
       13. The film according to  claim 10 , wherein the first polyethylene is a medium density polyethylene. 
     
     
       14. The film according to  claim 10 , wherein the second polyethylene is a linear low density polyethylene. 
     
     
       15. The film according to  claim 10 , wherein the film is substantially free of polypropylene. 
     
     
       16. The film according to  claim 10 , wherein the first outer layer comprises at least 80% by weight polyethylene based on the weight of the first outer layer. 
     
     
       17. The film according to any of  claim 10 , further comprising a second base layer, wherein the second base layer comprises at least one of a second polyolefin, a polyimide, an ethylene vinyl alcohol (EVOH), ethylene vinyl acetate (EVA), ethylene acrylic acid, and ethylene maleic anhydride. 
     
     
       18. An article comprising the film of  claim 10 , wherein the article is a flexible package, and wherein the film has a thickness of about 15 to about 300 microns.